Pneumatic tire and method of making same



July l0, 1934. R. w. sol-1L PNEUMATIC TIRE AND METHOD OF MAKING SAME Filed oop. 28, 1951 Patented July 10, 1934 PNEUMAUQ AND Memo!! .fermiamo SAME Ralph Sohle,Y AkronpOllio, assigner to Wingfoot Corporati n, Wilmington, Dell, werner@- Application `Qctoher 28, 1931, Serial No. 5715509' zoning; `(o1. 15gg-14) The present4 invention relates to plnellrnaticA` tires l'and methods of building the' same, and friorejl particularly to low-'pressure pneumatic,tireshavf` ing large erosssectionr, dime'i` is 'i 'mt ;y andren@ 'i tiveiysmalr bead diameters".

lleret'ofore,` the"const ruction of pneumatic'l 'res having large crossfsectionalareas and"s'rrrall"` bead diameters, such as' doughnuttires:fruuse in'airplaries'and land' vehicles; considerable diiiif-i r flucultyfhas beeriexperienced in formingthe tire carcasses ofeven, uniform 'strength'."lf they or! dinary flat band Amethods are employed in builld-v ir'igtiresVl i this type,`v the subsequent expansion 2:0?j`is used for making doughnu 'tir`es","the'plies, "when stitched 'down from the comparatively'large tread diameter to/ thev smallbeadv diameter, will"A pucker and bunch up` around` thev beads, giving very unsatisfactory' results. y

2Q It is an object of'therpresent invention to avoid, Y *t and overcome4 the foregoing'and other difficulties" and'u'ndesira'ble features'of yprior art methods,

tires, wherein the carcasses are of Very'unifo'rm 3Q; strength, 'and in'vvvhich'th'e cords and plies lie' "smoothly in proper relation to eachother; re

sultin'g in a: greatlyk improved product."`Y

Another object of theA invention is to provide a pneumatic tire oi the doughnut type, whereinl 35 the'various cords and plies lie in smooth `relatie 'i "i or desirable.' f

l to eachother Without bunchingl Another vobject lofjtheinvention is to provide a pneumatictire, 4wherein the marginal' edge portions of' the plies comprising the'tire carcass are l 41A)k split Ito form a plurality of strips' or tapeswhichf arestitched downto the proper position, so "that the cords will lie insmooth rel'ationto"eachotherf' giving, in effect,` a reinforced sidewallv Vireefz'irom shirrin'g, and in which all, of the vcords` areso related' as to facilitate'a-uniform load distribu-Y tionff Another object of 4,the invention is to provide a rapidi eicient' and pijacticalv method' of producinga low-pressure pneumatic tire having'supem 5o rior wear-*resisting and load-sustaining' 'qualit'i Frabetter 'understanding of the invention, reference may now be had to the accompanying drawing, wherein Fig. 1 is a diametrical, cross-sectional view St-1.A through a tire carcass and building form of one 5 isiividea, up and to provide a process for building doughnut be' coated with asuitableeimenp. '1t-will bes' Eig; 2j is an elevation of i the partially b uilttire- 'shownin' 'Figli' l," illustrating the 'next st,A intlie` buildingnprocess"`"` l "Rigi 3` i's al'siderelevationAoifthe tire comprising the" present' invention, illustrative ,"of fthe same" in an' iifiterrnediate I stagef of. the` building operal" anni l Fig 4 is a diametrieal,l cross-sectional, vievv 65Y 1"" g}` fisy aside 'elevation similar to Fig. 3k oi ,the tire" carcass" in ja furtzherV stageoff'the "buil" 'ng' process'; andr "E "Fig 6 fis"l alarge ycross-sectional A view through 79,.

me lcovrnpiteijt' Yiur-trie tread anesidimu; 'It 'will' be upderstood.,that the. present. imfenf icularly 'jad'apted `for:l they building of rlefl; mail. Gi .may 119i; be." upportg uponia; Silit'ible'l'blllsv ,01,1 Xl (119i "hOWrD "durng. ,the building` operations [asi may be found convenient" 90h knownv type. As is :usualin the tire' buildi iig`art,`

this, fibre "sifiheiliemltpreferably ,be cursos.,

the fabric back to Where it contacts with the tube 111,l

10, as best shown in Fig. 2. This operation is very readily accomplished when pickless cord fabric is employed, in that th bias-cut cor'lsare` held tdgether only by the rubber coating thereon and can be easily separated into strips on lines parallel to the direction in which the cords extend. x

'Ihe strips 16 are now successively folded radially inward upon the sidewalls of the tube 10 so that each strip as it is laid will partially overlap the preceding strip, and at the same time will lay smooth and flat with respect thereto. The ends of the strips 16 are left extending into the central portion of the tube 10 in the manner illustrated in Figs. 3 and 4, any number of other plies being now applied over the first ply, with or without the aid of a suitable bonding cement. The overlapping of the successive strips 16 makes possible a smooth lay of the cords without gathering or shirring in the sidewalls of the tire, and this facilitates uniform distribution of load on the cords when the tire is in use.

After the ply or plies are positioned as above described, the beads 20 are placed in the tire carcass, such beads comprising small bundles of wires, or any other inextensible means, if desired. As an alternative, the main strength of the bead portion of the carcass may be dependent upon the somewhat thicker portion of the carcass formed by the overlapping of the strips 16, in which case the non-extensible metallic beads previously referred to are not used. However, regardless of the particular type of bead used, the ends of the various strips 16 may now be folded back against the tire carcass in the manner illustrated in Fig.

V"5. This is accomplished by folding the ends of the outermost ply back over the bead rst and down against the tire sidewall in offset, overlapping relation, and thereafter similarly folding the .ends of the remaining plies back in turn. The 'bead portions of the tire are thus very rmly bonded into the tire carcass, and furthermore, the sidewalls of the tire carcass are built up and strengthened by the added material therein given by the folding back of the ends of the strips 16.

It will be understood that in certain instances the beads of the tire can be covered with the usual flipper strips, and that in such a construction, the strips 16 need not necessarily be folded around the beads, but can be of such length as to extend 'only down to the inner portion of the bead. While such a construction would be entirely practical, the illustrated 'embodiment is preferred because of the desirable added strength given to the tire carcass by actually folding the strips around the beads and back against the tire sidewalls.

A tread 22 and sidewall covers 24 are next applied to the tire carcass, and if desired, gum toes 26 may be added to the beads of the tire, as shown in Fig. 6. After the building operations have been completed, as above explained, the tire carcass may be removed from the tube 10, as by the deilation of the tube, and placed in a mold and vulcanized in any ordinary or preferred manner. In certain instances, the tube 10 may be left inside the tire carcass, either to be used as an airbag during vulcanization, or actually to form a permanent internal lining of rubber within the completed tire.

From the foregoing it will be apparent that a method has been provided for building tires of large cross-sectional dimensions and small bead incase? diameters, and wherein the cords lie in relatively flat, unbunchd relation to each other, and in whihfurthermre, the cord count in the fabric is substantially the same at the bead portion of the tire as at the tread portion. A tire carcass is formed with reinforced sidewalls adjacent the beads, whereby the stresses imposed upon the tire are more readily distributed and absorbed. This additional strengthening of the sidewalls and bead portions of the tire is particularly desirable in doughnut tires, inasmuch as the tire-supporting means is relatively small, as a result of which the stresses imposed upon the portions of the tire adjacent the hub or mounting rim are relatively greater per unit area.

Obviously, the various features of the improved tire, and the steps in the method of its manufacture, can be widely varied, as desired. For example, the extent of Contact of the plies at 14 with the supporting tube or form 10 may be increased or decreased to meet the requirements of a particular tire design. Also the length of the slits defining the strips 16 may be varied to give the proper degree of overlap in the sidewalls of' the tire. Again, the strips 16 may be of any predetermined width, dependent upon the type and size of the tire. Thus, in some instances, the strips may be relatively wide without bunching the cords, whereas in other cases the best results may be attained from using somewhat narrower strips.

Although I have illustrated only one embodiment of my invention, and have described that form in detail, it will be apparent to those skilled in the art that the invention is not so limited but that various modications may be made therein without departing from the spirit of the invention or from the scope of the appended claims.

What I claim is:

1. The method of making super-balloon tires which consists in providing an innatable form, wrapping a ply of rubberized fabric over the form, slitting the sides of the ply into strips, folding the strips over each other and in against the side of the form in overlapping, offset relation, applying a second ply of greater width to form longer strips in a similar manner to the form over the rst ply, applying means to define beads on the sides of the tire, folding the longer strips of the outermost ply baclr over the beads, folding the g the innermost ply lying on the outside of the tire carcass after they have been wrapped around the beads, the strips of the outermost ply extending around the beads between the strips of the innermost ply and the beads, said outer ply strips being longer than the inner ply strips and thus extending radially outwardly beyond the ends of the inner ply strips.

RALPH W. SOI-IL. 

